Power-operated hoists



Aug. 19, 1958 R. T. LUNN POWER-OPERATED HOISTS 3 Sheets-Sheet 1 Filed March 20, 1957 FIG./.

Attorneys R. T. LUNN POWER-OPERATED HOISTS Aug. 19, 1958 Filed March 20, 1957 3 Sheets- Sheet 2 Inventor A ftorneys Aug. 19, 1958 R. T. LUNN 2,848,129

' POWER-OPERATED HOISTS Filed March 20, 1957 v 3 Sheets-Sheet 3 Inventor MMTM mfbm Attorneys United States Patent "ice 2,848,129 POWER-OPERATED HOISTS Richard T. Lunn, London, England, assignor to A. C. E.

Machinery Limited, London, England, a British com- P y Application March 20, 1957, Serial No. 647,363

Claims priority, application Great Britain June 18, 1956 2 Claims. c1. 214 74o This invention relates to power-operated hoists used in connection with building operations.

In the erection of buildings it is frequently required to convey'comparatively small quantities of ready mixed concrete from the mixer to various building levels at which the concrete is poured into the forms of beams, columns and the like. The shuttering for these is more often than not without adjacent platforms and the concrete has to be raised from the floor at the base of the columns and this occurs from floor to floor as the building progresses. Moreover, the pouring position has to be varied at short intervals.

Previously used methods are wire-rope-suspended concrete containers from cranes or hoists which will not pour precisely and have to be steadied before tipping or an unnecessary degree of scaifolding has to be used to provide a working stage.

Floor-standing wheeled cranes cannot be easily moved past intersecting beams and are of considerable weight, and existing mobile platform hoists are too heavy except for ground level use.

The object of the present invention is to provide a mobile hoist of light but robust construction which is capable of raising concrete or other building material to a working height but which may be lowered to enable it to pass under obstructions below the working height.

According to the present invention there is provided a hoist for the purpose specified comprising a skip adapted to slide on a vertical mast and a power driven winch for raising the skip up the mast, the mast being formed in two sections of which the upper section can be lowered manually for movement in the decreased height condition.

An embodiment of the invention will now be described with reference to the accompanying drawings, of which Fig. l is a perspective view of the complete hoist showing the mast erected,

Fig. 2 is a side elevation showing the mast lowered for travelling,

Fig. 3 is an enlarged fragmentary view of the mast raising and lowering mechanism, and

Fig. 4 is a section on the line IVIV of Fig. 3.

The lower section 1 of the mast is formed at the front of a horizontal frame 2 and is braced by two splayed struts 3 extending from its top down to a roadwheel-carrying axle 4 at the rear of the horizontal frame or chassis. The bottom of the lower mast 1 extends below the chassis to form with the two road wheels 5 a triangular base.

The upper section 6 of the mast, or topmast, is pivotally connected adjacent to the top of the lower mast at a point 7 on an extension of the struts 3. The two sections of mast can be maintained in vertical axial alignment by a pin 8 passed through both sections below the pivot point 7 and additionally by a pair of down-hanging pivoted stays 9 fixed to a cross bar 10 engaging in slots formed in lugs 11 fixed to the struts 3. The cross bar Patented Aug. 19, 1958 '2 10 is prevented from coming out of the slots in the lugs by a locking lever 12. g

T o assist in the lowering of the topmast, there is provided a handle 13 rigidly connected to a radius rod 14 which is in turn pivotally connected tothe crossbar 10. It will be appreciated that the members 9 and 14 form the arms of a toggle mechanism.

To lower the top mast, the pin 8 is removed, the lever 12 rocked into the position shown dotted in Fig. 3, and the handle 13 rotated anti-clockwise (as viewed from the right of Fig. l). The final positions of the handle and topmast are shown in Fig. 2.

The skip is conveniently formed in the shape of a hopper 15 having an open top and an inclined funnelshaped bottom portion 16 adapted for pouring. The discharge opening in this lower portion is normally closed by, in this case, a pivoted trap 17 and pouring can be assisted by swinging down a hinged chute shown folded at 18. The skip is mounted on a carrier 19 provided with clip portions 20 adapted to embrace slide rails 21 on the mast sections. The latter may be formed as shown of right angle section girders arranged back to back but spaced apart by cross pieces 22. In this case,

the clips 29 on the skip carrier are curved pieces of metal adapted to engage around the projecting flanges of the girders. Wheels or rollers could, of course, be provided on the skip carrier but clips of the kind described have the advantage of lightness. In order to assist in pouring the concrete from the skip, the latter is arranged to rotate about its vertical axis through at least degrees. For this purpose, the upper end of the skip carries a cross bar 23 having an upwardly extending pivot pin 24. A similar pin 25 projects from the bottom of the skip on the centre line and both pins are journalled in bearings formed in upper and lower arms of the carrier.

In order to raise and lower the skip, a geared electric winch or a friction winch 26 driven by electric motor or by internal combustion enginev 27 is carried on the chassis over the road wheels. The lifting bond or cable 28 passes from the winch over two pulleys 29 carried in a crosshead 30 on the top mast and down to the skip carrier.

Safety arrangements provided in accordance with regulations include a top brake or trip not shown adapted to stop the winch when the skip carrier approaches the top of the topmast and a spring-operated cam brake 31 (Fig. 2) provided on the skip carrier and arranged to lock the latter to the mast if the lifting cable slackens or breaks.

In operation the unit is positioned so that the skip will raise the concrete close to one side of the beam or column to be filled and can then be pivoted radially to discharge the concrete into the precise forms. As filling proceeds the unit can be moved along in seconds irrespective of whether an obstructing beam occurs. Movement is almost equally easy in fully-erected or topmast-lowered form.

It will be seen that the invention provides an easily moved, and easily foldable mast hoist elevating a tracked rotatable bottom-discharge concrete skip, which can be fed conveniently with concrete by small adjacent concrete mixer, barrow loads, or from a feed hopper deposited by tower crane or the like.

It is self-standing when in use and can be moved rapidly and easily along the line of a beam, from column to column and easily taken from floor to floor.

I claim:

1. A hoist comprising a chassis, a mast comprising a lower section mounted in upright position on the chassis and an upper section movably connected to the lower section for raising and lowering movement relatively References Cited in the file of this patent UNITED STATES PATENTS Schmid May 28, 1929 Bushnell et al. Mar. 17, 1931 Roesner Oct. 23, 1934 Dempster et al May 26, 1953 

